// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.actions.mapmode;

import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.InputEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.Action;

import org.openstreetmap.josm.actions.JosmAction;
import org.openstreetmap.josm.gui.MainApplication;
import org.openstreetmap.josm.gui.MapFrame;
import org.openstreetmap.josm.gui.layer.Layer;
import org.openstreetmap.josm.gui.layer.OsmDataLayer;
import org.openstreetmap.josm.spi.preferences.Config;
import org.openstreetmap.josm.spi.preferences.PreferenceChangeEvent;
import org.openstreetmap.josm.spi.preferences.PreferenceChangedListener;
import org.openstreetmap.josm.tools.ImageProvider;
import org.openstreetmap.josm.tools.Logging;
import org.openstreetmap.josm.tools.PlatformHook;
import org.openstreetmap.josm.tools.PlatformManager;
import org.openstreetmap.josm.tools.Shortcut;

/**
 * A class implementing MapMode is able to be selected as an mode for map editing.
 * As example scrolling the map is a MapMode, connecting Nodes to new Ways is another.
 *
 * MapModes should register/deregister all necessary listeners on the map's view control.
 */
public abstract class MapMode extends JosmAction implements MouseListener, MouseMotionListener, PreferenceChangedListener {
    protected final Cursor cursor;
    protected boolean ctrl;
    protected boolean alt;
    protected boolean shift;
    /**
     * {@code true} if the meta key was pressed (the "Windows" key or the Mac "Command" key)
     * @since 18456
     */
    protected boolean meta;
    /**
     * {@code true} if the platform specific menu key was pressed ("ctrl" on Linux/Windows, "cmd" on Mac)
     * @see PlatformHook#getMenuShortcutKeyMaskEx()
     * @since 18456
     */
    protected boolean platformMenuShortcutKeyMask;

    /**
     * Constructor for mapmodes without a menu
     * @param name the action's text
     * @param iconName icon filename in {@code mapmode} directory
     * @param tooltip  a longer description of the action that will be displayed in the tooltip.
     * @param shortcut a ready-created shortcut object or null if you don't want a shortcut.
     * @param cursor cursor displayed when map mode is active
     * @since 11713
     */
    protected MapMode(String name, String iconName, String tooltip, Shortcut shortcut, Cursor cursor) {
        super(name, "mapmode/"+iconName, tooltip, shortcut, false);
        this.cursor = cursor;
        putValue("active", Boolean.FALSE);
    }

    /**
     * Constructor for mapmodes with a menu (no shortcut will be registered)
     * @param name the action's text
     * @param iconName icon filename in {@code mapmode} directory
     * @param tooltip  a longer description of the action that will be displayed in the tooltip.
     * @param cursor cursor displayed when map mode is active
     * @since 11713
     */
    protected MapMode(String name, String iconName, String tooltip, Cursor cursor) {
        putValue(NAME, name);
        new ImageProvider("mapmode", iconName).getResource().attachImageIcon(this);
        putValue(SHORT_DESCRIPTION, tooltip);
        this.cursor = cursor;
    }

    /**
     * Makes this map mode active.
     */
    public void enterMode() {
        Logging.debug("Entering map mode: {0}", getValue(Action.NAME));
        putValue("active", Boolean.TRUE);
        Config.getPref().addPreferenceChangeListener(this);
        readPreferences();
        MainApplication.getMap().mapView.setNewCursor(cursor, this);
        MainApplication.getMap().statusLine.setAutoLength(true);
        updateStatusLine();
    }

    /**
     * Makes this map mode inactive.
     */
    public void exitMode() {
        Logging.debug("Exiting map mode: {0}", getValue(Action.NAME));
        putValue("active", Boolean.FALSE);
        Config.getPref().removePreferenceChangeListener(this);
        MainApplication.getMap().mapView.resetCursor(this);
        MainApplication.getMap().statusLine.setAutoLength(true);
    }

    protected void updateStatusLine() {
        MapFrame map = MainApplication.getMap();
        if (map != null && map.statusLine != null) {
            map.statusLine.setHelpText(getModeHelpText());
            map.statusLine.repaint();
        }
    }

    /**
     * Returns a short translated help message describing how this map mode can be used, to be displayed in status line.
     * @return a short translated help message describing how this map mode can be used
     */
    public String getModeHelpText() {
        return "";
    }

    protected void readPreferences() {}

    /**
     * Call selectMapMode(this) on the parent mapFrame.
     */
    @Override
    public void actionPerformed(ActionEvent e) {
        if (MainApplication.isDisplayingMapView()) {
            MainApplication.getMap().selectMapMode(this);
        }
    }

    /**
     * Determines if layer {@code l} is supported by this map mode.
     * By default, all tools will work with all layers.
     * Can be overwritten to require a special type of layer
     * @param l layer
     * @return {@code true} if the layer is supported by this map mode
     */
    public boolean layerIsSupported(Layer l) {
        return l != null;
    }

    /**
     * Update internal ctrl, alt, shift mask from given input event.
     * @param e input event
     */
    protected void updateKeyModifiers(InputEvent e) {
        updateKeyModifiersEx(e.getModifiersEx());
    }

    /**
     * Update internal ctrl, alt, shift mask from given mouse event.
     * @param e mouse event
     */
    protected void updateKeyModifiers(MouseEvent e) {
        updateKeyModifiersEx(e.getModifiersEx());
    }

    /**
     * Update internal ctrl, alt, shift mask from given action event.
     * @param e action event
     * @since 12526
     */
    protected void updateKeyModifiers(ActionEvent e) {
        // ActionEvent does not have a getModifiersEx() method like other events :(
        updateKeyModifiersEx(mapOldModifiers(e.getModifiers()));
    }

    /**
     * Update internal ctrl, alt, shift, meta mask from given extended modifiers mask.
     * @param modifiers event extended modifiers mask
     * @since 12517
     */
    protected void updateKeyModifiersEx(int modifiers) {
        ctrl = (modifiers & InputEvent.CTRL_DOWN_MASK) != 0;
        alt = (modifiers & (InputEvent.ALT_DOWN_MASK | InputEvent.ALT_GRAPH_DOWN_MASK)) != 0;
        shift = (modifiers & InputEvent.SHIFT_DOWN_MASK) != 0;
        meta = (modifiers & InputEvent.META_DOWN_MASK) != 0;
        platformMenuShortcutKeyMask = (modifiers & PlatformManager.getPlatform().getMenuShortcutKeyMaskEx()) != 0;
    }

    /**
     * Map old (pre jdk 1.4) modifiers to extended modifiers (only for Ctrl, Alt, Shift).
     * @param modifiers old modifiers
     * @return extended modifiers
     */
    private static int mapOldModifiers(int modifiers) {
        if ((modifiers & ActionEvent.CTRL_MASK) != 0) {
            modifiers |= InputEvent.CTRL_DOWN_MASK;
        }
        if ((modifiers & ActionEvent.META_MASK) != 0) {
            modifiers |= InputEvent.META_DOWN_MASK;
        }
        if ((modifiers & ActionEvent.ALT_MASK) != 0) {
            modifiers |= InputEvent.ALT_DOWN_MASK;
        }
        /* Old modifier in InputEvent is deprecated, but ActionEvent has no ALT_GRAPH */
        if ((modifiers & InputEvent.ALT_GRAPH_MASK) != 0) {
            modifiers |= InputEvent.ALT_GRAPH_DOWN_MASK;
        }
        if ((modifiers & ActionEvent.SHIFT_MASK) != 0) {
            modifiers |= InputEvent.SHIFT_DOWN_MASK;
        }

        return modifiers;
    }

    protected void requestFocusInMapView() {
        if (isEnabled()) {
            // request focus in order to enable the expected keyboard shortcuts (see #8710)
            MainApplication.getMap().mapView.requestFocus();
        }
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        requestFocusInMapView();
    }

    @Override
    public void mouseExited(MouseEvent e) {
        // Do nothing
    }

    @Override
    public void mousePressed(MouseEvent e) {
        requestFocusInMapView();
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        // Do nothing
    }

    @Override
    public void mouseEntered(MouseEvent e) {
        // Do nothing
    }

    @Override
    public void mouseMoved(MouseEvent e) {
        // Do nothing
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        // Do nothing
    }

    @Override
    public void preferenceChanged(PreferenceChangeEvent e) {
        readPreferences();
    }

    /**
     * Determines if the given layer is a data layer that can be modified.
     * Useful for {@link #layerIsSupported(Layer)} implementations.
     * @param l layer
     * @return {@code true} if the given layer is a data layer that can be modified
     * @since 13434
     */
    protected boolean isEditableDataLayer(Layer l) {
        return l instanceof OsmDataLayer && !((OsmDataLayer) l).isLocked();
    }
}